Art-175 Is a Highly Efficient Antibacterial against Multidrug-Resistant Strains and Persisters of Pseudomonas aeruginosa

Artilysins constitute a novel class of efficient enzyme-based antibacterials. Specifically, they covalently combine a bacteriophage-encoded endolysin, which degrades the peptidoglycan, with a targeting peptide that transports the endolysin through the outer membrane of Gram-negative bacteria. Art-085, as well as Art-175, its optimized homolog with increased thermostability, are each composed of the sheep myeloid 29-amino acid (SMAP-29) peptide fused to the KZ144 endolysin. In contrast to KZ144, Art-085 and Art-175 pass the outer membrane and kill Pseudomonas aeruginosa, including multidrug-resistant strains, in a rapid and efficient (5 log units) manner. Time-lapse microscopy confirms that Art-175 punctures the peptidoglycan layer within 1 min, inducing a bulging membrane and complete lysis. Art-175 is highly refractory to resistance development by naturally oc-curring mutations. In addition, the resistance mechanisms against 21 therapeutically used antibiotics do not show cross-resis-tance to Art-175. Since Art-175 does not require an active metabolism for its activity, it has a superior bactericidal effect against P. aeruginosa persisters (up to>4 log units compared to that of the untreated controls). In summary, Art-175 is a novel antibac-terial that is well suited for a broad range of applications in hygiene and veterinary and humanmedicine, with a unique potential to target persister-driven chronic infections. During the so-called golden age of antibiotics in the 1960s,many thought the war against bacterial infections was won, but this confidence was proven to be premature. More than ever, the increasing emergence of multidrug-resistan